AU Lab lost windows, cannot open old settings nor save new ones

AU Lab lost windows, cannot open old settings nor save new ones I installed Soundflower 2.0b2 - which in contrary to 1.6.6 seems to work. AU Lab worked fine for two days, when I clicked accidentally on the close button all windows disappeared and cannot be revived - no new installation, cleaning PRam or other version helps. I can open the old settings, but nothing changes. If I create a new document, same thing happens - no windows and the menu is mainly greyed out. The only parts of the menu in black are: File/New, Open, Open Recent Window/Show Strip Library Debug/Clear AU Info Cache Help

How can I delete preferences and start from scratch?

My config: Macbook Pro 15" late 2011, Yosemite